Sir David Frost's party, 2 July

It's not, quite, that all hatchets are buried at summer parties. Yes, some extremely unlikely bedfellows, who have the rest of the year been at each other's throats - politically, culturally, intellectually - do pop up together, in photographs, in July, at swank events. What the rest of us should remember is that these pairings don't mean the characters are finally getting on with each other. They are always pictured talking to each other and smiling and looking happy because, frankly, they've been invited to the thing, and the rest of us haven't.

Sometimes, though, as in this fabulously of-the-moment vignette of Peter Mandelson and Alastair Campbell, caught through the trees at David Frost's Chelsea party in a way Monet would have adored, we can discern something wider: something more of history. They are, of course, as ever, not really talking to each other, but sharing their thoughts about someone else: a new arrival they both like; or the recent departure of some old git they both loathe. But these two bruisers, in their own very different ways, scalpel and cinder block ("I love you, but I can destroy you," Peter Mandelson once told Gordon Brown in an early Nineties phone call, terrifyingly), are the healthiest survivors of the New Labour project. Whatever it was.

Blair is away with the fairies and the money; Brown is doomed; all the other loyalists are either disgraced, disillusioned or biting the pillow in fear of next year. These two, despite once coming to blows in Brighton over the choice of Tony Blair's trousers for a photocall, have emerged largely unruined, unscathed. They were the cleverest beasts, and probably deserve to be allowed to pat each other on the back, with tender hesitation, over the scar tissue.

They may have been looking at David Cameron, also there. Wondering what, when he comes to power with his own project, is going to be significantly different from the New Labour project. Whatever it was. Can that have been a long conversation?